Increasing computing power and new user interface solutions such as touch screens are transforming mobile phones into versatile and powerful mobile computers. In order to put these capabilities fully into productive use, sufficiently large user interface surfaces may be provided. However, users also expect devices to be compact and easy to carry. For these reasons, various two-part form factors are common. Two-part devices typically have a compact position in which some user interface elements are hidden, and an extended position, in which additional user interface elements are available.